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The Influence of Selected Environmental Pollutants on Gametogenesis and Early Embryonic Development
Fenclová, Tereza ; Nevoral, Jan (advisor) ; Děd, Lukáš (referee) ; Sovadinová, Iva (referee)
The influence of selected environmental pollutants on gametogenesis and early embryonic development Ing. Tereza Fenclová Idiopatic infertility is a serious problem, which can be caused by exposure to endocrine disruptors, e.g. bisphenols. Bisphenol A, the most widely used bisphenol, is now being replaced in manufacturing processes due to its toxicity by its analogues, bisphenol S and F. While most of the scientific experiments examine the effect of toxic doses after direct exposure, this study provides results for exposure to real low doses after direct and indirect exposure. We assumed a negative effect of direct and indirect exposure to low doses of alternative bisphenols BPS and BPF on male and female reproduction at the level of gametes and embryos. The aim of this work is to evaluate the effect of direct exposure to mouse oocytes and sperm, to evaluate the effect of indirect exposure through breast milk to mouse oocytes, sperm, testicular tissue and the extent of damage to early embryonic development. Experimental ICR laboratory mice were exposed to low doses of bisphenols directly via drinking water or an oral gavage, or indirectly through the breast milk. Direct exposure to low doses of bisphenols affects the reproductive abilities of females mainly by malformations of the dividing spindle of...
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Male infertility and DNA germ cell breaks affected by the epigenetic factor PRDM9
Kusari, Fitore ; Trachtulec, Zdeněk (advisor) ; Děd, Lukáš (referee) ; Liška, František (referee)
DNA-binding histone-3-lysine-4,36-trimethyltransferase PRDM9 specifies meiotic recombination hotspots in mice, rats and humans. Interallelic variation at the Prdm9 locus plays a role in hybrid male sterility. Sterile mouse F1 hybrid male offspring from the PWD × C57BL/6J (B6) cross exhibit meiosis breakdown reminiscent of that observed in Prdm9-deficient B6 sterile mice. However, reciprocal (B6 × PWD)F1 hybrids and some rodent models lacking PRDM9, i.e., PWD and SHR rat males execute meiotic recombination, produce sperm, raising the possibility that PRDM9's role may extend beyond meiosis. Here I demonstrate that PRDM9 is important for post- meiotic male gamete development and release. Unlike their parents, (B6 × PWD)F1 generated spermatozoa of lower quantity and motility but higher percentage of deformations, thus resembling oligoasthenoteratozoospermic (OAT) (semi)sterile men. Histopathological and (ultra)structural analysis revealed compromised spermiogenesis characterized by acrosome detachment and aberrant nucleus elongation in (B6 × PWD)F1 hybrids. Consequently, F1 spermatozoa had malformed acrosomes and nuclear DNA breaks with elevated base oxidation. While deletion of one Prdm9 copy improved sperm phenotypes in (B6 × PWD)F1, copy number gains of the surrounding genes had the opposite effect....
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Effect of endocrine disruptor bisphenol S on human health and reproduction
Procházková, Bára ; Petr, Jaroslav (advisor) ; Děd, Lukáš (referee)
Bisphenol S (BPS) is an environmental pollutant that has replaced bisphenol A (BPA) in plastic and paper products since 2011 as a safer "BPA-free" alternative. However, due to its rapid replacement, its potential adverse effects have not been investigated in detail, and due to its structural similarity to BPA, many studies suggest that it acts, like BPA, as an endocrine disruptor. Its use is wide and BPS is globally widespread, found in the environment and has been detected in both animal and human tissues. Nevertheless, an overall effect of BPS on an organism remains unclear. This work is focusing on gathering sources for its effect on reproductive ability and its association with metabolic disorders.
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The localization of maternal RNAs during early development
Kováčiková, Petra ; Šindelka, Radek (advisor) ; Děd, Lukáš (referee)
The maternal determination of a developmental plan has been described in many animal species. The most well-known examples are found in the embryogenesis of C. elegans and D. melanogaster. In vertebrates, these studies are often limited by the size of oocytes to just a small subset of model organisms. The most comprehensive research can be found dealing with the early development in the frog, Xenopus laevis. Its oocytes, displaying differently pigmented animal and vegetal hemispheres, are patterned by an asymmetric distribution of maternal factors. These proteins and RNAs of maternal origin are stored in the oocyte and provide the only source of cell differentiation until the zygotic genome activation. Here, we address the role of RNA localization in this process. We assessed the localization patterns of both, maternal mRNAs and lncRNAs and found that, in addition to protein coding transcripts, lncRNAs also form concentration gradients along the animal-vegetal axis. Furthermore, using RT-qPCR tomography, we have now been able to demonstrate a difference between actively localized extremely animal group and spontaneously localized animal group of transcripts, a distinction emerging from the transcriptome characterization performed in our laboratory. Additionally, we found that the extremely animal...
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Post-copulatory sexual selection and sperm phenotypes
Bílková, Karolína ; Albrecht, Tomáš (advisor) ; Děd, Lukáš (referee)
Postcopulatory sexual selection has two basic components, sperm competition and cryptic female choice. In this thesis I summarize available data of the influence of postcopulatory sexual selection on sperm morhology and phenotype, focusing on both vertebrates and selected invertebrate taxa. In the first part of my thesis, I provide an overview of sperm phenotype adaptations that are influenced by the sperm competition and may closely determine male fertilization success. These are the length of sperm, sperm swimming speed and motility, longevity of sperm and the amount of ejaculate produced. Sperm phenotypes that evolve under strong postocopulatory selection may also involve morphological adaptations alowing sperm to mutually cooperate in the female reproductive tract. The cryptic female choise, in which female selectively use sperm after the sperm enters her reproductive tract, and the coevolution of sperm morphology and female reproductive tract is presented in the second part of this thesis. Powered by TCPDF (www.tcpdf.org)
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Effect of estrogens and endocrine distruptors on mammalian sperm in vitro and male reproductive parameters in vivo
Děd, Lukáš ; Pěknicová, Jana (advisor) ; Jonáková, Věra (referee) ; Linhart, Otomar (referee)
The endocrine system is one of the most important regulatory systems in human and animal bodies and almost all physiological processes are regulated by it. Human and animal reproduction are largely regulated by different hormones and their proper and well regulated functions are essential for successful production of the gametes, fertilization and related processes, development of the embryo and fetus, initiation of puberty and production of the offspring. Estrogens have generally been considered as primarily female hormones. However, there is increasing evidence of their important impact on male reproductive functions. This was well documented by production of estrogen receptor knock-out male mice, which are infertile. Estrogens and estrogen receptors are also very frequent targets of endocrine disruption. Endocrine disruptors are natural or artificial compounds that, at certain doses, can interfere with the endocrine functions in human and wildlife. This interference can include specific binding to the hormonal receptor, influencing the production, elimination and transport of the natural hormones and also not well documented mechanisms including epigenetic regulations. In the presented work, our aim was to evaluate the effects of natural estrogens and endocrine disruptors on male reproductive...
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Distribution of CD46 and β1 integrin molecules with respect to different membrane structures of the sperm head
Šebková, Nataša ; Frolíková, Michaela ; Děd, Lukáš ; Dvořáková-Hortová, Kateřina
CD46 protein plays an important role during fertilization and its role is associated with acrosome stability. CD46 is probably involved in signalling pathways triggering the acrosome reaction (AR). It also associates through membrane integrins with specific MAP kinases involved in the AR. Our aim was to monitor the dynamics of relocation of CD46 and β1 integrin during sperm maturation and its preparation for the fertilization. The dependence of this localization changes on the dynamic of actin cytoskeleton was studied. Our results show the changes in the localization of these proteins associated with the AR and their co-localization was observed using proximity ligation assay. After the AR CD46 and β1 integrin spreads across the sperm head, entering the post-acrosomal compartment, and permeates the borders of different domains. It was shown previously that actin dynamics is necessary for acrosome reaction-associated translocation of Izumo1 protein that is required for sperm-egg fusion. Therefore Latrunculin A was used during sperm incubation. The co-incubation of capacitated sperm with Latrunculin A leads to a decrease of the percentages of sperm, which express relocation pattern after induced AR. 3D models and visualizations of potential membrane processes responsible for the relocation of proteins from the acrosomal area to the other compartments of the sperm head were prepared. Our results deliver new information that proteins CD46 and β1 integrin undergo dynamic relocation towards the sites of sperm-egg fusion during the AR in vitro. The inhibitor of actin dynamics abrogates significantly the AR-associated changes in proteins localization. We speculate that this relocation is of importance for the successful sperm-egg interaction, adhesion and subsequent gamete fusion.
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Expression of selected proteins in sperm in men with normal and pathological spermiograms using monoclonal antibodies
Pěknicová, Jana ; Čapková, Jana ; Dorosh, Andriy ; Margaryan, Hasmik ; Kubátová, Alena ; Děd, Lukáš
Recent studies show that infertility in human populations it affects an estimated 15% of couples of reproductive age. Male infertility is the primary cause for 60% of these cases. For these reasons, we analyzed the acrosomal and sperm surface proteins in men with normal and pathological spermiograms. We found that intra-acrosome proteins: TERA (Transitional endoplasmic reticulum ATPase), GAPDHS (Sperm Glyceraldehyde-3-phosphate dehydrogenase), and PRKAR2A (C-AMP-dependent protein kinase II, PRKAR2A), which can be identified using our monoclonal antibodies, are different express in healthy men and men with astenozoospermia (with reduced sperm motility), and with a significantly reduced expression in the astenozoospermia. These proteins are involved in energy metabolism and apoptosis of the cells, and some of them in the sperm-egg interaction; therefore, they have an important role in reproduction. On the other hand, there were no statistically significant differences in the expression of surface proteins (Appolipoprotein J (Clusterin) and Semenogelin). Our findings show that astenozoospermia as a complex disorder of the semen is often combined with other pathological conditions that are not diagnosed by the semen analysis. Therefore monoclonal antibodies are so suitable instrument for the detection of proteins associated with the pathology of the sperm in the semen with low sperm motility. In general, monoclonal antibodies against the sperm proteins are an appropriate tool to detect sperm quality in reproductive medicine.
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